Oil burner electrode and mounting means therefor



Feb. 16, 1943. w. w. SLAGHT OIL BURNER ELECTRODE AND MOUNTING MEANS THEREFOR Filed March 15, 1941 W/LL/m W JLHHT WWW Patented Feb. 16,

OIL BURNER W1)! AND MOUNTING MEANS THEREFOR William W. Slaght, Rocky River, Ohio, assignor to Cleveland Steel Products Corporation, Cleveland, Ohio, a corporation of Ohio Application Man-.1113, 1941, Serial No. scans a Claims. (01. 115-115) This invention relates to an electrode mounting assembly for'oil burning apparatus of the wall flame type.

In oil burning apparatus of the wall flame type, oil and air are discharged horizontally from a rotary member centrally located in the combustion chamber, which chamber is closed by a hearth member of refractory material, the oil being intercepted near the periphery of the combustion chamber by a substantially continuous combustion ring for ignition by a pair of spark electrodes. Since the advent of the metal combustion ring it has been the practice to employ the ring itself as one of the spark electrodes, this electrode being grounded.

The present invention has to do with the means for mounting the other electrode which extends through the combustion chamber hearth for connection with the hot side of the ignition circuit. Due to the specifications of the underwriters laboratories, it is necessary to provide between the electrode proper and the nearest metal part a non-conductive surface of considerable length which may be provided by the walls of an air gap. Heretofore it has been the practice to employ a cup-shaped member of frangible refractory material surrounding the insulator of the electrode. Experience has shown that, due to the expansion of the refractory hearth material, this cup-shaped member frequently becomes broken.

One of the objects of the present invention is to provide a mounting assembly for an electrode employed in oil burning apparatus of the wall flame type which will not become destroyed or broken by the expansion of the surrounding hearth material.

Another object is to provide an electrode mounting assembly which is simple in construction, easy to install, and relatively inexpensive to manufacture.

Another object is to provide an electrode mounting assembly of improved construction which will permit easy adjustment of the mounted electrode and yet will rigidly maintain the electrode in the desired position.

With the above and other objects in view the present invention consists of certain features of construction and combinations of parts to be hereinafter described with reference to the accompanying drawing, and then claimed.

In the drawing, Fig. 1 is a fragmentary vertical section taken through the combustion chamber of a furnace in which the present invention is incorporated;

Fig. 2 is an upper plan view of the electrode assembly showing the same associated with the combustion ring of a rotary wall flame oil burning apparatus; and

Fig. 3 is a tranverse section taken substantially on the line 3-4 of Fig. 1, showing the clamping means.

With reference to the accompanying drawing in which like numerals refer to like parts throughout the several views, there is shown in Fig. 1 a fragmentary vertical section of a portion of the hearth and combustion chamber in which the electrode and its mounting assembly are incorporated. The numeral ill represents an upright furnace wall which is provided with a horizontal hearth plate H. The hearth plate ii is covered with and supports a hearth bed I! of suitable non-metallic refractory material extending to the wall III which forms the vertical wall of the combustion chamber. The hearth bed l2 forms the bottomof the combustion chamber.

Extending upwardly from the hearth plate II and through the hearth bed I2 is a metallic member l3 having a horizontal portion II which supports a combustion ring l5, here shown as being of U-shaped metal having an outer vertical leg i6 and a shorter inner leg lid. The inner surface of the outer vertical leg l6 of the ring [5 which projects above the inner leg lid is the oil intercepting and vaporizing wall of the oil burning apparatus. This wall also forms one electrode of the igniter for the passage of a spark for igniting the oil intercepted by the inner surface of the vertical leg It. This metal ring in practice is grounded. The other electrode [1, to which the present invention relates, extends vertically through the hearth bed I! and plate ll so as to have a terminal end l8 disposed below the hearth plate II and an upper end portion l9 disposed above the hearth l2. As shown in Fig. l. the upper end portion 19 is reversely bent and terminates in a spark tip 20 spaced a sufficient distance from the inner surface of the metal wall It so that a spark gap is provided therebetween.

Surrounding the electrode I1 is an insulator 2| which is of a material that is a non-conductor of electricity. The electrode i1 is held against longitudinal and rotary movement with respect to the insulator 2| by means of small cars 22 pinched out from the metal of the electrode which fit within slots 23 formed in the upper end face of the insulator and by means of a nut 24 threaded to the terminal end ii of the electrode. The electrode insulator II is shown to be square in cross section. However, it is to be understood that it may be round or of any other suitable shape in cross section.

The means for mounting the electrode l1 and by means of a closure plate 26a having a central aperture 21 therethrough preferably conforming in shape to the cross sectional shape of the insulator 2|. The insulator 2| extends through this aperture to provide an external portion and an internal portion, the internal portion extending from the closure plate 28a substantially to the plane of flange 25.

Secured-to the closure plate 28a by means of welding or any other suitable means is a bracket means 28 having a depending portion 23. The depending portion 23 is provided with spaced legs 30 which surround the electrode insulator 2| and terminate in spaced parallel portions 3| at one side oi. the insulator. These legs constitute a clamp for the insulator and are provided with a screw 32 and nut 33 threaded thereon for moving the parallel portions 3| toward each other to firmly clamp electrode insulator 2| in position. Upon loosening the nut 33, the insulator 2! is movable longitudinally of the surrounding shell 25 so as to provide for vertical adjustment of the insulator 2| and supported electrode I! relative to the shell 25. It is to be noted that the shell or sleeve 25 is circumferentially spaced from the insulator 2| to provide an open well or space surrounding the insulator.

Fitting over the shell 25, which preferably is made of corrosion and heat resstant metal such as stainless sheet steel, and welded to the underside oi. the flange 26 is an annular connecting member 34 of similar sheet metal which is provided at one side with an upwardly extending portion 35. The portion 35 is reversely bent adjacent its end to provide an inverted hook portion 35.

The hearth plate ii is formed with an aperture 38 and in the assembled position of the electrode mounting assembly the shell 25 extends through the hearth bed l2 and the aperture 38 with a circumferential clearance between the walls of the latter and the shell and so that a portion of the shell or sleeve is disposed below the hearth plate I with the underside of the annular member 34 resting upon the upper surface of the hearth bed and with the inverted hook portion 36 fitting over the upper edge of the shorter inner leg |5a of the combustion ring i5. I

By fitting or interlocking the hook portion 35 over the leg I 6a the entire electrode assembly just described is held in fixed position so as to maintain the desired spark gap between the spark tip 20 of the electrode and the inner surface of the outer leg i6 of the combustion ring l5.

The electrode assembly herein described facilitates replacement of the insulator 2| should the same become broken or otherwise defective in operation. Loosening of the nut 33 releases the grip of the clamp legs 30 on the insulator so that the latter may bewithdrawn from the cup or sleeve upwardly through the closure plate or member 26a. The new or replacement insulator having the electrode |3 secured therein may be then inserted in the holder by passing the lower end of the new .insulator downwardly through the closure 26a and clamping the insulator and electrode in place by means of the leg portions 30 of the bracket 23. This electrode replacement or renewal may be made without disturbing the hearth material I: or the retaining cup or sleeve 25. The square or non-circular shape of the insulator 2| and the corresponding shape of the clamping bracket 28 prevents rotation of the insulator and the electrode during assembly. This is of advantage to the servicemen who is making the repair to the furnace or boiler because the electrode assembly is usually relativeiy inaccessible and the service man is frequently unable simultaneously to see both the upper end and the lower end of the electrode. Nonrotatability of the insulator obtained by the present invention holds the electrode in correct position relative to the fixed electrode l5 while the service man, unable to observe the position of the tip end 20 relative to the fixed electrode |5,'secures the electrode in place beneath the hearth by the clamp bracket 28.

The hook portion 36 of the member 34 of the electrode assembly affords an interlocking conmotion between the retainer or sleeve 25 and the fixed electrode i5. Accordingly, the space or gap between the spark tip 20 of the electrode l1 and the fixed electrode I5 is established by the manufacturer and upon proper assembly of the parts in the field the spark gap is that previously determined by the manufacturer. Thus, the

variation that would be apt to occur without an interlocking connection between the two elec-" trodes is avoided and improved performance 'and general operating characteristics result.

As previously described the insulator 2|, which preferably is made of porcelain, china or other vitreous material, and the electrode I! carried thereby are relatively movable in a longitudinal or axial direction by loosening the nut 33 to release the clamp 28 and permit such movement whereby the vertical position of the spark tip 20 may be adjusted with respect to the surface of the leg iii of the combustion ring. Ii desired. the annular member 34 may be eliminated and the upwardly extending portion'35 which forms the inverted hook portion may be formed as an integral part of the flange 26. Also, if desired the closure plate 26c may be an integral Part of the shell 25.

By reason of the spacing of the shell 25 from the insulator 2! a relatively large circumferential air space is provided, which by reason of the portion of the insulator 2| located within the shell 25 presents a relatively long continuous non-conductive surface between that portion of the electrode i1 adjacent the upper end of the insulator 2| and the nearest metal surface.

It is to be noted that the entire electrode assembly constitutes a unitary structure for assembly with the oil burning apparatus.

One advantageous feature of the invention is that since the shell 25 is of sheet metal in contrast to refractory material heretofore used it will not be fractured or broken by expansion of the refractory material constituting the hearth bed which is subjected to the intense heat in the combustion chamber. Another advantageous feature is that the sheet metal shell will rapidly disdescription, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What I claim is:

l. A mounting assembly for an electrode for oil burning apparatus of the wall flame type comprising a tubular cup having an open top and a closed bottom, said cup being of sheet metal, said closed bottom having an aperture therethrough, an terial extending through said aperture and having a portion without said cup and a portion within said cup, said latter portion extending substantially to the open end of said cup in spaced relation with respect to the longitudinal wall thereof, bracket means rigidly carried by said closed insulator tube of non-conductive mabottom and having a depending portion provided with spaced clamping legs extending around said insulator and terminating in spaced ends and means urging said ends toward each other to clamp said legs around said insulator tube, and an electrode element extending through said insulator tube in fixed position.

2. A mounting assembly for an electrode for oil burning apparatus of the wall flame type comprising a tubular cup having an open top and a closed bottom, said cup being of sheet metal, said closed bottom having an aperture therethrough, an insulator-tube of non-conductive material extending through said aperture and having a portion without said cup and a portion within said cup. said latter portion extending substantially to the open end or said cup in spaced relation with respect to the longitudinal wall thereof, bracket means rigidly carried by said closed bottom and having means securely clamping said insulator tube against movement, said bracket means being welded to said bottom, the clamping means thereof conforming to the external configuration of said insulator tube, and an electrode element extending through said tube.

3. A mounting assembly for an electrode for oil burning apparatus of the wall flame type comprising a tubular cup having an open top and a closed bottom, said cup being of sheet metal, said closed bottom having an aperture therethrough, an insulator tube of non-conductive material extending through said aperture and having a portion without said cup and a portion within said cup, said latter portion extending substantially to the open end of said cup in spaced relation with respect to the longitudinal wall thereof, brackst means rigidly carried by said closed bottom and having means securely clamping said insulator tube against movement, the open end of said cup having an outwardly extending flange and an upwardly extending portion associated with said flange for cooperation with an adjoining part of the oil burning apparatus for mounting said electrode mounting assembly in fixed position, and an electrode element extending through said tube.

4. In an oil burner, a combustion initiating structure including a wall for receiving fuel and vaporizing the same and electrode means associated with said wall, an electrode assembly disposed adjacent said structure and comprising an elongated sheet metal cup having an open top and a substantially closed bottom formed with a central aperture, an elongated dielectric tube extending longitudinally through said cup and having connection with the bottom of the latter, an electrode element extending through the tube and having a spark tip disposed adjacent said electrode means of the fuel vaporizing wall. and means on the electrode assembly for hooking the same to the combustion initiating structure to retain the electrode element in predetermined spaced relation to the electrode means.

5. In an oil burner, a combustion initiating structure including a wall for receiving fuel and vaporizing the same and electrode means associated with said wall, an electrode assembly disposed adiacent said structure and comprising an elongated sheet metal cup having an open top and a substantially closed bottom formed with a central aperture. an elongated dielectric tube of non-circular cross section extending longitudinally through said cup, non-circular means at the bottom of the cup for receiving and supp rting the tube and holding the latter against turning in the cup, an electrode element extending through the tube and having a lateral portion provided at one end with a spark tip, locating means for holding the electrode element in predetermined rotative relation to the tube, and means for retaining the electrode assembly in predetermined relation to the combustion initiating structure whereby the spark tip is supported in predetermined relation to the electrode means. 6. In an oil burner, a combustion initiating structure including a wall for receiving fuel and vaporizing the same and electrode means associated with said wall, an electrode assembly disposed adjacent said structure and comprising an elongated sheet metal cup having an open top and a substantially closed bottom formed with a central aperture, an elongated dielectric tube of non-circular cross section extending longitudinally through said cup, non-circular means at the bottom of the cup for grippingly receiving the tube and supporting the same in different positions of longitudinal adjustment relative to the cup and for holding the tube against turning in the cup, an electrode element extending through the tube and having a lateral portion provided at one end with a spark tip, locating means for holding the electrode element in predetermined rotative relation to the tube, and means for retaining the electrode assembly in predetermined relation to the combustion initiating structure whereby the spark tip is supported in predetermined relation to the electrode means.

7. An electrode assembly for oil burning apparatus comprising a sheet metal cup havin an open top and a substantially closed bottom formed with a central aperture, an elongated dielectric tube of non-circular cross section extending longitudinally through said cup, means at the bottom of the cup having a non-circular passage for receiving and guiding the tube for longitudinal sliding movement through the cup bottom in adjusting the tube longitudinally relative to the cup while retaining the tube in predetermined rotational position relative to the cup and having a gripping device for holding the tube in adjusted position, and an electrode element extending through the tube and held against relative turning therein.

8. An electrode assembly for oil burning apparatus comprising a sheet metal cup having an open top and a substantially closed bottom formed with a central aperture, an elongated dielectric tube of substantially uniform non-circular cross section from end to end extending longitudinally through said cup, means at the bottom of the,

cup having a non-circular passage for receiving and guiding the tube for longitudinal sliding movement through the cup bottom in adjusting the tube longitudinally relativeto the cup while retaining the tube in predetermined rotetional position relative to the cup-and having a.- gripping device for holding the tube in adJusted position, and an electrode element 7 extending through the tube and held against relative turnin; therein, said electrode element having an angularly disposed portion on iteupper end extending laterally beyond the cup periphery, the tube and element being withdrawable as a. unit through the open top 01 the cup upon being re- 5 leased by the gripping device.

WILLIAM w. SLAGHT. 

